Commit 3563822b authored by David Howells's avatar David Howells Committed by Wen Zhiwei
Browse files

rxrpc: Fix a race between socket set up and I/O thread creation 

stable inclusion
from stable-v6.6.55
commit cdf4bbbdb956d7426f687f38757ebca2a2759a0f
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IB0MX4

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=cdf4bbbdb956d7426f687f38757ebca2a2759a0f



--------------------------------

commit bc212465326e8587325f520a052346f0b57360e6 upstream.

In rxrpc_open_socket(), it sets up the socket and then sets up the I/O
thread that will handle it.  This is a problem, however, as there's a gap
between the two phases in which a packet may come into rxrpc_encap_rcv()
from the UDP packet but we oops when trying to wake the not-yet created I/O
thread.

As a quick fix, just make rxrpc_encap_rcv() discard the packet if there's
no I/O thread yet.

A better, but more intrusive fix would perhaps be to rearrange things such
that the socket creation is done by the I/O thread.

Fixes: a275da62 ("rxrpc: Create a per-local endpoint receive queue and I/O thread")
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
cc: yuxuanzhe@outlook.com
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241001132702.3122709-2-dhowells@redhat.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarWen Zhiwei <wenzhiwei@kylinos.cn>
parent 2004b49f

net/rxrpc/ar-internal.h

+1 −1
Original line number Diff line number Diff line
@@ -1066,7 +1066,7 @@ bool rxrpc_direct_abort(struct sk_buff *skb, enum rxrpc_abort_reason why, 
int rxrpc_io_thread(void *data);

static inline void rxrpc_wake_up_io_thread(struct rxrpc_local *local)

{

	wake_up_process(local->io_thread);

	wake_up_process(READ_ONCE(local->io_thread));

}



static inline bool rxrpc_protocol_error(struct sk_buff *skb, enum rxrpc_abort_reason why)

net/rxrpc/io_thread.c

+8 −2
Original line number Diff line number Diff line
@@ -27,11 +27,17 @@ int rxrpc_encap_rcv(struct sock *udp_sk, struct sk_buff *skb) 
{

	struct sk_buff_head *rx_queue;

	struct rxrpc_local *local = rcu_dereference_sk_user_data(udp_sk);

	struct task_struct *io_thread;



	if (unlikely(!local)) {

		kfree_skb(skb);

		return 0;

	}

	io_thread = READ_ONCE(local->io_thread);

	if (!io_thread) {

		kfree_skb(skb);

		return 0;

	}

	if (skb->tstamp == 0)

		skb->tstamp = ktime_get_real();
@@ -47,7 +53,7 @@ int rxrpc_encap_rcv(struct sock *udp_sk, struct sk_buff *skb) 
#endif



	skb_queue_tail(rx_queue, skb);

	rxrpc_wake_up_io_thread(local);

	wake_up_process(io_thread);

	return 0;

}
@@ -554,7 +560,7 @@ int rxrpc_io_thread(void *data) 
	__set_current_state(TASK_RUNNING);

	rxrpc_see_local(local, rxrpc_local_stop);

	rxrpc_destroy_local(local);

	local->io_thread = NULL;

	WRITE_ONCE(local->io_thread, NULL);

	rxrpc_see_local(local, rxrpc_local_stopped);

	return 0;

}

net/rxrpc/local_object.c

+1 −1
Original line number Diff line number Diff line
@@ -232,7 +232,7 @@ static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net) 
	}



	wait_for_completion(&local->io_thread_ready);

	local->io_thread = io_thread;

	WRITE_ONCE(local->io_thread, io_thread);

	_leave(" = 0");

	return 0;